Sustaining Daily Activity Levels May Offset Depression Risk
Those who kept active during COVID-19 lockdowns were at lower depression risk.
Posted Mar 11, 2021 |
- On average, walking activity declined from 10,000 to 4,600 steps per day after stay-at-home orders began in March 2020.
- Maintaining physical activity habits at pre-pandemic baseline levels from March to July 2020 was associated with a lower risk of depression.
- However, restoring daily physical activity through a short-term intervention did not immediately improve well-being among study participants.
Even though exercise isn't a magic bullet or panacea that can instantly cure the mental health disruptions that have occurred during COVID-19 lockdowns, new research suggests that those who stayed active in the early months of the pandemic (March to July 2020) experienced less depression than those who became more sedentary during the same period. These findings (Giuntella, Hyde, Saccardo, & Sadoff, 2021) were published on March 2 in Proceedings of the National Academy of Sciences.
Four researchers from three universities conducted this multidisciplinary study: Osea Giuntella of the University of Pittsburgh's Department of Economics, Kelly Hyde and Silvia Saccardo from the Department of Social and Decision Sciences at Carnegie Mellon University, and Sally Sadoff of UCSD's School of Management.
For this study, the researchers used a longitudinal dataset that linked biometric and survey data from several cohorts of college-aged young adults (N = 682) before and during the COVID-19 pandemic.
Changes in Habits and Depression During the Pandemic
The study's objective was to investigate lifestyle and mental health disruptions that occurred from February (before classes moved online) to July 2020 by documenting changes in people's daily physical activity, sleep habits, use of time, and overall mental health.
In addition to self-reporting their daily lifestyle habits by filling out surveys, participants wore fitness trackers (Fitbits) that monitored their activity levels 24/7. Participants started providing Fitbit data and lifestyle surveys in February; they continued their participation from home after classes switched to online learning.
At the onset of the pandemic in March 2020, sleep increased by 25-30 minutes per night (on average) among study participants. People's average number of steps per day declined from 10,000 to 4,600. Screen time more than doubled to five hours per day. And the daily time people spent socializing dropped to less than 30 minutes per day, on average.
Throughout the first few months of this pandemic, from March to July 2020, the proportion of participants at risk for depression ranged from 46 to 61 percent; according to the authors, this statistic represents a "90 percent increase in depression rates compared to the same population just prior to the pandemic."
The Relationship Between Physical Activity and Depression
As lockdowns and stay-at-home orders disrupted people's daily physical activity levels, depression risk skyrocketed. There was a relationship at the group level between depression risk and the extent to which physical activity had declined. "Those who experienced declines of one to two hours of physical activity per day were most at risk for depression during the pandemic, while participants who were able to maintain their daily habits were at the lowest risk," the authors note.
However, when it comes to physical activity's ability to alleviate depressive symptoms—and the possibility that people who were inherently less prone to depression were also more likely to stay active—there's a noteworthy twist to these findings. Even though staying physically active during stay-at-home mandates was associated with fewer depressive symptoms, when study participants who'd become more sedentary started walking 10,000 steps per day, they didn't experience an immediate antidepressant effect.
"Our findings also suggest a puzzle: Disruptions to physical activity and mental health are strongly associated, but [the] restoration of physical activity through a short-term intervention does not help improve mental health," the authors wrote.
"This raises many possible explanations, including that the impact of physical activity may require a longer-term intervention," Sadoff said in a news release. "At the same time, our results clearly show that those who maintained physical exercise throughout the pandemic were the most resilient and least likely to suffer from depression."
Of note: This study did not investigate how other intensities of aerobic exercise such as high-intensity interval training (HIIT) or moderate-intensity cardio workouts (e.g., jogging) affect depressive symptoms after 14 days.
Previous research (Brush et al., 2020) found that moderate-intensity aerobic exercise "demonstrated antidepressant efficacy among adults with major depression" more than light-intensity stretching alone. It would be interesting for future studies to examine if walking 10,000 steps per day at a brisk pace affected people's mental health differently than walking the same number of daily steps at a slow (light-intensity) pace. (See "New Clues About the Antidepressant Power of Aerobic Exercise.")
In addition to the possibility that the antidepressant effects of cardio only kick in at moderate-to-vigorous physical activity (MVPA) exertion levels, other social dynamics may come into play. For example, the feeling of connectedness and community that one experiences during a spin class or while doing cardio side-by-side with other gymgoers instantly evaporated when workout facilities were shuttered during the pandemic.
"The pandemic tightened the relationship between the maintenance of lifestyle habits and mental health," Sadoff and coauthors concluded. "More research is needed to understand how to improve both physical and mental health during such periods of large disruption."
Osea Giuntella, Kelly Hyde, Silvia Saccardo, and Sally Sadoff. "Lifestyle and Mental Health Disruptions During COVID-19." PNAS (First published: March 02, 2021) DOI: 10.1073/pnas.2016632118
C. J. Brush, Greg Hajcak, Anthony J. Bocchine, Andrew A. Ude, Kristina M. Muniz, Dan Foti, and Brandon L. Alderman. "A Randomized Trial of Aerobic Exercise for Major Depression: Examining Neural Indicators of Reward and Cognitive Control as Predictors and Treatment Targets." Psychological Medicine (First published online: August 24, 2020) DOI: 10.1017/S0033291720002573